The present invention relates to an immunological analyzing apparatus and analyzing method using a liquid reagent in which particles (bead particles) bonded with a antigen or antibody are suspended and, more in particular, it relates to an immunological analyzer having a control mechanism for a stirring mechanism that stirs a liquid regent prior to the dispensing operation of the liquid reagent to a reaction vessel, as well as immunological analysis method.
In a heterogeneous immunological analyzing method, slide glass, micro chip, silicious sand such as kaolin, micro-plate, for example, of 96 wells, plastic beads, polypropylene beads, polycarbonate beads, latex beads, gelatin beads or magnetic beads are used as a solid phase body, and final reaction products are formed on the surface thereof. The final reaction products are bonded with enzyme such as peroxidaze, alkali phosphatase and galactosidase, light emitting substance such as acrydium ester or ruthenium, fluorescent substance such as fluororescein or rhodamine, antibody, antigen or avidin labeled with rare earth coloring substance such as europium. Coloration, light emission, fluorescence or phosphorescence is observed by adding a substrate, a light emitting liquid or a coloring liquid to a labeled body and, if necessary, changing pH, applying voltage or controlling the temperature to an optimal condition. By measuring them, presence or absence of an aimed object and the amount of the object to be analyzed in the specimen can be estimated.
The solid phase body is used as it is, or coated with a substance that concerns the formation of final reaction products such as an antibody, Fab, Fc, antigen, avidin, biotin or protein A, or a substance that inhibits a non-specific reaction not based on the antigen-antibody reaction irrespective of the formation of the final reaction products including the object to be analyzed.
Among the solid phase bodies, particulate or spherical solid phase body is maintained as it is as a dried product of the solid phase body or being suspended in a preservation liquid, diluent or buffer solution such as dispersion solution. Among them, particle beads suspended in the preservation solution, diluent or buffer solution may sometime float or precipitate when they are not stirred due to the difference in the specific gravity between the beads and the liquid. Then, it is ordinary to stir the particle beads before the dispensing operation to the reaction vessel upon measurement so that the particles are uniformly suspended in the buffer solution. If they are not suspended homogeneously, the result of analysis varies and no exact analysis can be attained.
Japanese Patent Laid-Open No. Hei 4-47266 discloses a technique of setting a standard stirring interval and compulsorily stirring the liquid reagent based on the interval time in order to dispense the reagent in a state where the fine particles suspended in the liquid reagent are uniformly dispersed.
In a case where a stirring rod or a stirrer is put in a buffer to stir the liquid by the rotation of the stirring rod or the stirrer, since a portion thereof is immersed in the particle beads reagent upon stirring, contamination (reagent carry-over) may possibly occur between reagents different from each other by way of the stirring rod or the stirrer. The reagent carry-over also worsens the reproducibility of the result of analysis.
However, the stirring method disclosed in Japanese Patent Laid-Open No. Hei 4-47266 takes a notice only on the standard interval for uniform dispersion of micro particles but no consideration has been taken for the carry-over.
An object of this invention is to provide an immunological analysis apparatus and analysis method using a liquid reagent in which micro particles bonded with an antigen or antibody are suspended and which can provide high reproducibility for the result of analysis.